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34 * @(#)kern_sig.c 8.7 (Berkeley) 4/18/94
35 * $FreeBSD: src/sys/kern/kern_sig.c,v 1.72.2.17 2003/05/16 16:34:34 obrien Exp $
38 #include "opt_ktrace.h"
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/kernel.h>
43 #include <sys/sysproto.h>
44 #include <sys/signalvar.h>
45 #include <sys/resourcevar.h>
46 #include <sys/vnode.h>
47 #include <sys/event.h>
49 #include <sys/nlookup.h>
50 #include <sys/pioctl.h>
52 #include <sys/fcntl.h>
55 #include <sys/ktrace.h>
56 #include <sys/syslog.h>
58 #include <sys/sysent.h>
59 #include <sys/sysctl.h>
60 #include <sys/malloc.h>
61 #include <sys/interrupt.h>
62 #include <sys/unistd.h>
63 #include <sys/kern_syscall.h>
64 #include <sys/vkernel.h>
66 #include <sys/signal2.h>
67 #include <sys/thread2.h>
68 #include <sys/spinlock2.h>
70 #include <machine/cpu.h>
71 #include <machine/smp.h>
73 static int coredump(struct lwp *, int);
74 static char *expand_name(const char *, uid_t, pid_t);
75 static int dokillpg(int sig, int pgid, int all);
76 static int sig_ffs(sigset_t *set);
77 static int sigprop(int sig);
78 static void lwp_signotify(struct lwp *lp);
79 static void lwp_signotify_remote(void *arg);
80 static int kern_sigtimedwait(sigset_t set, siginfo_t *info,
81 struct timespec *timeout);
82 static void proc_stopwait(struct proc *p);
84 static int filt_sigattach(struct knote *kn);
85 static void filt_sigdetach(struct knote *kn);
86 static int filt_signal(struct knote *kn, long hint);
88 struct filterops sig_filtops =
89 { FILTEROP_MPSAFE, filt_sigattach, filt_sigdetach, filt_signal };
91 static int kern_logsigexit = 1;
92 SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW,
94 "Log processes quitting on abnormal signals to syslog(3)");
97 * Can process p send the signal sig to process q? Only processes within
98 * the current reaper or children of the current reaper can be signaled.
99 * Normally the reaper itself cannot be signalled, unless initok is set.
101 #define CANSIGNAL(q, sig, initok) \
102 ((!p_trespass(curproc->p_ucred, (q)->p_ucred) && \
103 reaper_sigtest(curproc, p, initok)) || \
104 ((sig) == SIGCONT && (q)->p_session == curproc->p_session))
107 * Policy -- Can real uid ruid with ucred uc send a signal to process q?
109 #define CANSIGIO(ruid, uc, q) \
110 ((uc)->cr_uid == 0 || \
111 (ruid) == (q)->p_ucred->cr_ruid || \
112 (uc)->cr_uid == (q)->p_ucred->cr_ruid || \
113 (ruid) == (q)->p_ucred->cr_uid || \
114 (uc)->cr_uid == (q)->p_ucred->cr_uid)
117 SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW,
118 &sugid_coredump, 0, "Enable coredumping set user/group ID processes");
120 static int do_coredump = 1;
121 SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW,
122 &do_coredump, 0, "Enable/Disable coredumps");
125 * Signal properties and actions.
126 * The array below categorizes the signals and their default actions
127 * according to the following properties:
129 #define SA_KILL 0x01 /* terminates process by default */
130 #define SA_CORE 0x02 /* ditto and coredumps */
131 #define SA_STOP 0x04 /* suspend process */
132 #define SA_TTYSTOP 0x08 /* ditto, from tty */
133 #define SA_IGNORE 0x10 /* ignore by default */
134 #define SA_CONT 0x20 /* continue if suspended */
135 #define SA_CANTMASK 0x40 /* non-maskable, catchable */
136 #define SA_CKPT 0x80 /* checkpoint process */
139 static int sigproptbl[NSIG] = {
140 SA_KILL, /* SIGHUP */
141 SA_KILL, /* SIGINT */
142 SA_KILL|SA_CORE, /* SIGQUIT */
143 SA_KILL|SA_CORE, /* SIGILL */
144 SA_KILL|SA_CORE, /* SIGTRAP */
145 SA_KILL|SA_CORE, /* SIGABRT */
146 SA_KILL|SA_CORE, /* SIGEMT */
147 SA_KILL|SA_CORE, /* SIGFPE */
148 SA_KILL, /* SIGKILL */
149 SA_KILL|SA_CORE, /* SIGBUS */
150 SA_KILL|SA_CORE, /* SIGSEGV */
151 SA_KILL|SA_CORE, /* SIGSYS */
152 SA_KILL, /* SIGPIPE */
153 SA_KILL, /* SIGALRM */
154 SA_KILL, /* SIGTERM */
155 SA_IGNORE, /* SIGURG */
156 SA_STOP, /* SIGSTOP */
157 SA_STOP|SA_TTYSTOP, /* SIGTSTP */
158 SA_IGNORE|SA_CONT, /* SIGCONT */
159 SA_IGNORE, /* SIGCHLD */
160 SA_STOP|SA_TTYSTOP, /* SIGTTIN */
161 SA_STOP|SA_TTYSTOP, /* SIGTTOU */
162 SA_IGNORE, /* SIGIO */
163 SA_KILL, /* SIGXCPU */
164 SA_KILL, /* SIGXFSZ */
165 SA_KILL, /* SIGVTALRM */
166 SA_KILL, /* SIGPROF */
167 SA_IGNORE, /* SIGWINCH */
168 SA_IGNORE, /* SIGINFO */
169 SA_KILL, /* SIGUSR1 */
170 SA_KILL, /* SIGUSR2 */
171 SA_IGNORE, /* SIGTHR */
172 SA_CKPT, /* SIGCKPT */
173 SA_KILL|SA_CKPT, /* SIGCKPTEXIT */
211 if (sig > 0 && sig < NSIG)
212 return (sigproptbl[_SIG_IDX(sig)]);
217 sig_ffs(sigset_t *set)
221 for (i = 0; i < _SIG_WORDS; i++)
223 return (ffs(set->__bits[i]) + (i * 32));
228 * Allows us to populate siginfo->si_pid and si_uid in the target process
229 * (p) from the originating thread (td). This function must work properly
230 * even if a kernel thread is sending the signal.
232 * NOTE: Signals are not queued, so if multiple signals are received the
233 * signal handler will only see the most recent pid and uid for any
234 * given signal number.
237 sigsetfrompid(thread_t td, struct proc *p, int sig)
241 if ((sap = p->p_sigacts) == NULL)
244 sap->ps_frominfo[sig].pid = td->td_proc->p_pid;
245 sap->ps_frominfo[sig].uid = td->td_ucred->cr_uid;
247 sap->ps_frominfo[sig].pid = 0;
248 sap->ps_frominfo[sig].uid = 0;
256 kern_sigaction(int sig, struct sigaction *act, struct sigaction *oact)
258 struct thread *td = curthread;
259 struct proc *p = td->td_proc;
261 struct sigacts *ps = p->p_sigacts;
263 if (sig <= 0 || sig > _SIG_MAXSIG)
266 lwkt_gettoken(&p->p_token);
269 oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)];
270 oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)];
272 if (SIGISMEMBER(ps->ps_sigonstack, sig))
273 oact->sa_flags |= SA_ONSTACK;
274 if (!SIGISMEMBER(ps->ps_sigintr, sig))
275 oact->sa_flags |= SA_RESTART;
276 if (SIGISMEMBER(ps->ps_sigreset, sig))
277 oact->sa_flags |= SA_RESETHAND;
278 if (SIGISMEMBER(ps->ps_signodefer, sig))
279 oact->sa_flags |= SA_NODEFER;
280 if (SIGISMEMBER(ps->ps_siginfo, sig))
281 oact->sa_flags |= SA_SIGINFO;
282 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDSTOP)
283 oact->sa_flags |= SA_NOCLDSTOP;
284 if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDWAIT)
285 oact->sa_flags |= SA_NOCLDWAIT;
289 * Check for invalid requests. KILL and STOP cannot be
292 if (sig == SIGKILL || sig == SIGSTOP) {
293 if (act->sa_handler != SIG_DFL) {
294 lwkt_reltoken(&p->p_token);
300 * Change setting atomically.
302 ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask;
303 SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]);
304 if (act->sa_flags & SA_SIGINFO) {
305 ps->ps_sigact[_SIG_IDX(sig)] =
306 (__sighandler_t *)act->sa_sigaction;
307 SIGADDSET(ps->ps_siginfo, sig);
309 ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler;
310 SIGDELSET(ps->ps_siginfo, sig);
312 if (!(act->sa_flags & SA_RESTART))
313 SIGADDSET(ps->ps_sigintr, sig);
315 SIGDELSET(ps->ps_sigintr, sig);
316 if (act->sa_flags & SA_ONSTACK)
317 SIGADDSET(ps->ps_sigonstack, sig);
319 SIGDELSET(ps->ps_sigonstack, sig);
320 if (act->sa_flags & SA_RESETHAND)
321 SIGADDSET(ps->ps_sigreset, sig);
323 SIGDELSET(ps->ps_sigreset, sig);
324 if (act->sa_flags & SA_NODEFER)
325 SIGADDSET(ps->ps_signodefer, sig);
327 SIGDELSET(ps->ps_signodefer, sig);
328 if (sig == SIGCHLD) {
329 if (act->sa_flags & SA_NOCLDSTOP)
330 p->p_sigacts->ps_flag |= PS_NOCLDSTOP;
332 p->p_sigacts->ps_flag &= ~PS_NOCLDSTOP;
333 if (act->sa_flags & SA_NOCLDWAIT) {
335 * Paranoia: since SA_NOCLDWAIT is implemented
336 * by reparenting the dying child to PID 1 (and
337 * trust it to reap the zombie), PID 1 itself
338 * is forbidden to set SA_NOCLDWAIT.
341 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT;
343 p->p_sigacts->ps_flag |= PS_NOCLDWAIT;
345 p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT;
347 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN)
348 ps->ps_flag |= PS_CLDSIGIGN;
350 ps->ps_flag &= ~PS_CLDSIGIGN;
353 * Set bit in p_sigignore for signals that are set to SIG_IGN,
354 * and for signals set to SIG_DFL where the default is to
355 * ignore. However, don't put SIGCONT in p_sigignore, as we
356 * have to restart the process.
358 * Also remove the signal from the process and lwp signal
361 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN ||
362 (sigprop(sig) & SA_IGNORE &&
363 ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) {
364 SIGDELSET_ATOMIC(p->p_siglist, sig);
365 FOREACH_LWP_IN_PROC(lp, p) {
366 spin_lock(&lp->lwp_spin);
367 SIGDELSET(lp->lwp_siglist, sig);
368 spin_unlock(&lp->lwp_spin);
370 if (sig != SIGCONT) {
371 /* easier in ksignal */
372 SIGADDSET(p->p_sigignore, sig);
374 SIGDELSET(p->p_sigcatch, sig);
376 SIGDELSET(p->p_sigignore, sig);
377 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)
378 SIGDELSET(p->p_sigcatch, sig);
380 SIGADDSET(p->p_sigcatch, sig);
383 lwkt_reltoken(&p->p_token);
388 sys_sigaction(struct sigaction_args *uap)
390 struct sigaction act, oact;
391 struct sigaction *actp, *oactp;
394 actp = (uap->act != NULL) ? &act : NULL;
395 oactp = (uap->oact != NULL) ? &oact : NULL;
397 error = copyin(uap->act, actp, sizeof(act));
401 error = kern_sigaction(uap->sig, actp, oactp);
402 if (oactp && !error) {
403 error = copyout(oactp, uap->oact, sizeof(oact));
409 * Initialize signal state for process 0;
410 * set to ignore signals that are ignored by default.
413 siginit(struct proc *p)
417 for (i = 1; i <= NSIG; i++)
418 if (sigprop(i) & SA_IGNORE && i != SIGCONT)
419 SIGADDSET(p->p_sigignore, i);
423 * Reset signals for an exec of the specified process.
426 execsigs(struct proc *p)
428 struct sigacts *ps = p->p_sigacts;
432 lp = ONLY_LWP_IN_PROC(p);
435 * Reset caught signals. Held signals remain held
436 * through p_sigmask (unless they were caught,
437 * and are now ignored by default).
439 while (SIGNOTEMPTY(p->p_sigcatch)) {
440 sig = sig_ffs(&p->p_sigcatch);
441 SIGDELSET(p->p_sigcatch, sig);
442 if (sigprop(sig) & SA_IGNORE) {
444 SIGADDSET(p->p_sigignore, sig);
445 SIGDELSET_ATOMIC(p->p_siglist, sig);
446 /* don't need spinlock */
447 SIGDELSET(lp->lwp_siglist, sig);
449 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
453 * Reset stack state to the user stack.
454 * Clear set of signals caught on the signal stack.
456 lp->lwp_sigstk.ss_flags = SS_DISABLE;
457 lp->lwp_sigstk.ss_size = 0;
458 lp->lwp_sigstk.ss_sp = NULL;
459 lp->lwp_flags &= ~LWP_ALTSTACK;
461 * Reset no zombies if child dies flag as Solaris does.
463 p->p_sigacts->ps_flag &= ~(PS_NOCLDWAIT | PS_CLDSIGIGN);
464 if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN)
465 ps->ps_sigact[_SIG_IDX(SIGCHLD)] = SIG_DFL;
469 * kern_sigprocmask() - MP SAFE ONLY IF p == curproc
471 * Manipulate signal mask. This routine is MP SAFE *ONLY* if
475 kern_sigprocmask(int how, sigset_t *set, sigset_t *oset)
477 struct thread *td = curthread;
478 struct lwp *lp = td->td_lwp;
479 struct proc *p = td->td_proc;
482 lwkt_gettoken(&p->p_token);
485 *oset = lp->lwp_sigmask;
492 SIGSETOR(lp->lwp_sigmask, *set);
495 SIGSETNAND(lp->lwp_sigmask, *set);
499 lp->lwp_sigmask = *set;
507 lwkt_reltoken(&p->p_token);
518 sys_sigprocmask(struct sigprocmask_args *uap)
521 sigset_t *setp, *osetp;
524 setp = (uap->set != NULL) ? &set : NULL;
525 osetp = (uap->oset != NULL) ? &oset : NULL;
527 error = copyin(uap->set, setp, sizeof(set));
531 error = kern_sigprocmask(uap->how, setp, osetp);
532 if (osetp && !error) {
533 error = copyout(osetp, uap->oset, sizeof(oset));
542 kern_sigpending(struct __sigset *set)
544 struct lwp *lp = curthread->td_lwp;
546 *set = lwp_sigpend(lp);
555 sys_sigpending(struct sigpending_args *uap)
560 error = kern_sigpending(&set);
563 error = copyout(&set, uap->set, sizeof(set));
568 * Suspend process until signal, providing mask to be set
574 kern_sigsuspend(struct __sigset *set)
576 struct thread *td = curthread;
577 struct lwp *lp = td->td_lwp;
578 struct proc *p = td->td_proc;
579 struct sigacts *ps = p->p_sigacts;
582 * When returning from sigsuspend, we want
583 * the old mask to be restored after the
584 * signal handler has finished. Thus, we
585 * save it here and mark the sigacts structure
588 lp->lwp_oldsigmask = lp->lwp_sigmask;
589 lp->lwp_flags |= LWP_OLDMASK;
592 lp->lwp_sigmask = *set;
593 while (tsleep(ps, PCATCH, "pause", 0) == 0)
595 /* always return EINTR rather than ERESTART... */
600 * Note nonstandard calling convention: libc stub passes mask, not
601 * pointer, to save a copyin.
606 sys_sigsuspend(struct sigsuspend_args *uap)
611 error = copyin(uap->sigmask, &mask, sizeof(mask));
615 error = kern_sigsuspend(&mask);
624 kern_sigaltstack(struct sigaltstack *ss, struct sigaltstack *oss)
626 struct thread *td = curthread;
627 struct lwp *lp = td->td_lwp;
628 struct proc *p = td->td_proc;
630 if ((lp->lwp_flags & LWP_ALTSTACK) == 0)
631 lp->lwp_sigstk.ss_flags |= SS_DISABLE;
634 *oss = lp->lwp_sigstk;
637 if (ss->ss_flags & ~SS_DISABLE)
639 if (ss->ss_flags & SS_DISABLE) {
640 if (lp->lwp_sigstk.ss_flags & SS_ONSTACK)
642 lp->lwp_flags &= ~LWP_ALTSTACK;
643 lp->lwp_sigstk.ss_flags = ss->ss_flags;
645 if (ss->ss_size < p->p_sysent->sv_minsigstksz)
647 lp->lwp_flags |= LWP_ALTSTACK;
648 lp->lwp_sigstk = *ss;
659 sys_sigaltstack(struct sigaltstack_args *uap)
665 error = copyin(uap->ss, &ss, sizeof(ss));
670 error = kern_sigaltstack(uap->ss ? &ss : NULL, uap->oss ? &oss : NULL);
672 if (error == 0 && uap->oss)
673 error = copyout(&oss, uap->oss, sizeof(*uap->oss));
678 * Common code for kill process group/broadcast kill.
679 * cp is calling process.
686 static int killpg_all_callback(struct proc *p, void *data);
689 dokillpg(int sig, int pgid, int all)
691 struct killpg_info info;
692 struct proc *cp = curproc;
703 allproc_scan(killpg_all_callback, &info, 0);
707 * zero pgid means send to my process group.
718 * Must interlock all signals against fork
720 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE);
721 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
723 p->p_stat == SZOMB ||
724 (p->p_flags & P_SYSTEM) ||
725 !CANSIGNAL(p, sig, 0)) {
732 lockmgr(&pgrp->pg_lock, LK_RELEASE);
735 return (info.nfound ? 0 : ESRCH);
739 killpg_all_callback(struct proc *p, void *data)
741 struct killpg_info *info = data;
743 if (p->p_pid <= 1 || (p->p_flags & P_SYSTEM) ||
744 p == curproc || !CANSIGNAL(p, info->sig, 0)) {
749 ksignal(p, info->sig);
754 * Send a general signal to a process or LWPs within that process.
756 * Note that new signals cannot be sent if a process is exiting or already
757 * a zombie, but we return success anyway as userland is likely to not handle
763 kern_kill(int sig, pid_t pid, lwpid_t tid)
767 if ((u_int)sig > _SIG_MAXSIG)
772 struct lwp *lp = NULL;
775 * Send a signal to a single process. If the kill() is
776 * racing an exiting process which has not yet been reaped
777 * act as though the signal was delivered successfully but
778 * don't actually try to deliver the signal.
780 if ((p = pfind(pid)) == NULL) {
781 if ((p = zpfind(pid)) == NULL)
787 lwkt_gettoken_shared(&p->p_token);
788 if (!CANSIGNAL(p, sig, 1)) {
789 lwkt_reltoken(&p->p_token);
793 lwkt_reltoken(&p->p_token);
797 * NOP if the process is exiting. Note that lwpsignal() is
798 * called directly with P_WEXIT set to kill individual LWPs
799 * during exit, which is allowed.
801 if (p->p_flags & P_WEXIT) {
806 lwkt_gettoken_shared(&p->p_token);
807 lp = lwp_rb_tree_RB_LOOKUP(&p->p_lwp_tree, tid);
809 lwkt_reltoken(&p->p_token);
814 lwkt_reltoken(&p->p_token);
817 lwpsignal(p, lp, sig);
826 * If we come here, pid is a special broadcast pid.
827 * This doesn't mix with a tid.
833 case -1: /* broadcast signal */
834 t = (dokillpg(sig, 0, 1));
836 case 0: /* signal own process group */
837 t = (dokillpg(sig, 0, 0));
839 default: /* negative explicit process group */
840 t = (dokillpg(sig, -pid, 0));
847 sys_kill(struct kill_args *uap)
851 error = kern_kill(uap->signum, uap->pid, -1);
856 sys_lwp_kill(struct lwp_kill_args *uap)
859 pid_t pid = uap->pid;
862 * A tid is mandatory for lwp_kill(), otherwise
863 * you could simply use kill().
869 * To save on a getpid() function call for intra-process
870 * signals, pid == -1 means current process.
873 pid = curproc->p_pid;
875 error = kern_kill(uap->signum, pid, uap->tid);
880 * Send a signal to a process group.
883 gsignal(int pgid, int sig)
887 if (pgid && (pgrp = pgfind(pgid)))
888 pgsignal(pgrp, sig, 0);
892 * Send a signal to a process group. If checktty is 1,
893 * limit to members which have a controlling terminal.
895 * pg_lock interlocks against a fork that might be in progress, to
896 * ensure that the new child process picks up the signal.
899 pgsignal(struct pgrp *pgrp, int sig, int checkctty)
904 * Must interlock all signals against fork
908 lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE);
909 LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
910 if (checkctty == 0 || p->p_flags & P_CONTROLT)
913 lockmgr(&pgrp->pg_lock, LK_RELEASE);
919 * Send a signal caused by a trap to the current lwp. If it will be caught
920 * immediately, deliver it with correct code. Otherwise, post it normally.
922 * These signals may ONLY be delivered to the specified lwp and may never
923 * be delivered to the process generically.
926 trapsignal(struct lwp *lp, int sig, u_long code)
928 struct proc *p = lp->lwp_proc;
929 struct sigacts *ps = p->p_sigacts;
932 * If we are a virtual kernel running an emulated user process
933 * context, switch back to the virtual kernel context before
934 * trying to post the signal.
936 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
937 struct trapframe *tf = lp->lwp_md.md_regs;
939 vkernel_trap(lp, tf);
942 if ((p->p_flags & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) &&
943 !SIGISMEMBER(lp->lwp_sigmask, sig)) {
944 lp->lwp_ru.ru_nsignals++;
946 if (KTRPOINT(lp->lwp_thread, KTR_PSIG))
947 ktrpsig(lp, sig, ps->ps_sigact[_SIG_IDX(sig)],
948 &lp->lwp_sigmask, code);
950 (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig,
951 &lp->lwp_sigmask, code);
952 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
953 if (!SIGISMEMBER(ps->ps_signodefer, sig))
954 SIGADDSET(lp->lwp_sigmask, sig);
955 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
957 * See kern_sigaction() for origin of this code.
959 SIGDELSET(p->p_sigcatch, sig);
960 if (sig != SIGCONT &&
961 sigprop(sig) & SA_IGNORE)
962 SIGADDSET(p->p_sigignore, sig);
963 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
966 lp->lwp_code = code; /* XXX for core dump/debugger */
967 lp->lwp_sig = sig; /* XXX to verify code */
968 lwpsignal(p, lp, sig);
973 * Find a suitable lwp to deliver the signal to. Returns NULL if all
974 * lwps hold the signal blocked.
976 * Caller must hold p->p_token.
978 * Returns a lp or NULL. If non-NULL the lp is held and its token is
982 find_lwp_for_signal(struct proc *p, int sig)
985 struct lwp *run, *sleep, *stop;
988 * If the running/preempted thread belongs to the proc to which
989 * the signal is being delivered and this thread does not block
990 * the signal, then we can avoid a context switch by delivering
991 * the signal to this thread, because it will return to userland
994 lp = lwkt_preempted_proc();
995 if (lp != NULL && lp->lwp_proc == p) {
997 lwkt_gettoken(&lp->lwp_token);
998 if (!SIGISMEMBER(lp->lwp_sigmask, sig)) {
999 /* return w/ token held */
1002 lwkt_reltoken(&lp->lwp_token);
1006 run = sleep = stop = NULL;
1007 FOREACH_LWP_IN_PROC(lp, p) {
1009 * If the signal is being blocked by the lwp, then this
1010 * lwp is not eligible for receiving the signal.
1013 lwkt_gettoken(&lp->lwp_token);
1015 if (SIGISMEMBER(lp->lwp_sigmask, sig)) {
1016 lwkt_reltoken(&lp->lwp_token);
1021 switch (lp->lwp_stat) {
1025 lwkt_reltoken(&sleep->lwp_token);
1031 lwkt_reltoken(&stop->lwp_token);
1040 if (lp->lwp_flags & LWP_SINTR) {
1042 lwkt_reltoken(&lp->lwp_token);
1046 lwkt_reltoken(&stop->lwp_token);
1054 lwkt_reltoken(&lp->lwp_token);
1060 lwkt_reltoken(&lp->lwp_token);
1063 lwkt_reltoken(&lp->lwp_token);
1076 else if (sleep != NULL)
1083 * Send the signal to the process. If the signal has an action, the action
1084 * is usually performed by the target process rather than the caller; we add
1085 * the signal to the set of pending signals for the process.
1088 * o When a stop signal is sent to a sleeping process that takes the
1089 * default action, the process is stopped without awakening it.
1090 * o SIGCONT restarts stopped processes (or puts them back to sleep)
1091 * regardless of the signal action (eg, blocked or ignored).
1093 * Other ignored signals are discarded immediately.
1095 * If the caller wishes to call this function from a hard code section the
1096 * caller must already hold p->p_token (see kern_clock.c).
1101 ksignal(struct proc *p, int sig)
1103 lwpsignal(p, NULL, sig);
1107 * The core for ksignal. lp may be NULL, then a suitable thread
1108 * will be chosen. If not, lp MUST be a member of p.
1110 * If the caller wishes to call this function from a hard code section the
1111 * caller must already hold p->p_token.
1116 lwpsignal(struct proc *p, struct lwp *lp, int sig)
1122 if (sig > _SIG_MAXSIG || sig <= 0) {
1123 kprintf("lwpsignal: signal %d\n", sig);
1124 panic("lwpsignal signal number");
1127 KKASSERT(lp == NULL || lp->lwp_proc == p);
1130 * We don't want to race... well, all sorts of things. Get appropriate
1133 * Don't try to deliver a generic signal to an exiting process,
1134 * the signal structures could be in flux. We check the LWP later
1140 lwkt_gettoken(&lp->lwp_token);
1142 lwkt_gettoken(&p->p_token);
1143 if (p->p_flags & P_WEXIT)
1147 prop = sigprop(sig);
1150 * If proc is traced, always give parent a chance;
1151 * if signal event is tracked by procfs, give *that*
1152 * a chance, as well.
1154 if ((p->p_flags & P_TRACED) || (p->p_stops & S_SIG)) {
1158 * Do not try to deliver signals to an exiting lwp other
1159 * than SIGKILL. Note that we must still deliver the signal
1160 * if P_WEXIT is set in the process flags.
1162 if (lp && (lp->lwp_mpflags & LWP_MP_WEXIT) && sig != SIGKILL) {
1163 lwkt_reltoken(&lp->lwp_token);
1170 * If the signal is being ignored, then we forget about
1171 * it immediately. NOTE: We don't set SIGCONT in p_sigignore,
1172 * and if it is set to SIG_IGN, action will be SIG_DFL here.
1174 if (SIGISMEMBER(p->p_sigignore, sig)) {
1176 * Even if a signal is set SIG_IGN, it may still be
1177 * lurking in a kqueue.
1179 KNOTE(&p->p_klist, NOTE_SIGNAL | sig);
1181 lwkt_reltoken(&lp->lwp_token);
1184 lwkt_reltoken(&p->p_token);
1189 if (SIGISMEMBER(p->p_sigcatch, sig))
1196 * If continuing, clear any pending STOP signals for the whole
1199 if (prop & SA_CONT) {
1200 lwkt_gettoken(&p->p_token);
1201 SIG_STOPSIGMASK_ATOMIC(p->p_siglist);
1202 lwkt_reltoken(&p->p_token);
1205 if (prop & SA_STOP) {
1207 * If sending a tty stop signal to a member of an orphaned
1208 * process group, discard the signal here if the action
1209 * is default; don't stop the process below if sleeping,
1210 * and don't clear any pending SIGCONT.
1212 if ((prop & SA_TTYSTOP) && p->p_pgrp->pg_jobc == 0 &&
1213 action == SIG_DFL) {
1215 lwkt_reltoken(&lp->lwp_token);
1218 lwkt_reltoken(&p->p_token);
1223 lwkt_gettoken(&p->p_token);
1224 SIG_CONTSIGMASK_ATOMIC(p->p_siglist);
1225 p->p_flags &= ~P_CONTINUED;
1226 lwkt_reltoken(&p->p_token);
1229 if (p->p_stat == SSTOP) {
1231 * Nobody can handle this signal, add it to the lwp or
1232 * process pending list
1234 lwkt_gettoken(&p->p_token);
1235 if (p->p_stat != SSTOP) {
1236 lwkt_reltoken(&p->p_token);
1239 sigsetfrompid(curthread, p, sig);
1241 spin_lock(&lp->lwp_spin);
1242 SIGADDSET(lp->lwp_siglist, sig);
1243 spin_unlock(&lp->lwp_spin);
1245 SIGADDSET_ATOMIC(p->p_siglist, sig);
1249 * If the process is stopped and is being traced, then no
1250 * further action is necessary.
1252 if (p->p_flags & P_TRACED) {
1253 lwkt_reltoken(&p->p_token);
1258 * If the process is stopped and receives a KILL signal,
1259 * make the process runnable.
1261 if (sig == SIGKILL) {
1262 proc_unstop(p, SSTOP);
1263 lwkt_reltoken(&p->p_token);
1264 goto active_process;
1268 * If the process is stopped and receives a CONT signal,
1269 * then try to make the process runnable again.
1271 if (prop & SA_CONT) {
1273 * If SIGCONT is default (or ignored), we continue the
1274 * process but don't leave the signal in p_siglist, as
1275 * it has no further action. If SIGCONT is held, we
1276 * continue the process and leave the signal in
1277 * p_siglist. If the process catches SIGCONT, let it
1278 * handle the signal itself.
1280 * XXX what if the signal is being held blocked?
1282 * Token required to interlock kern_wait().
1283 * Reparenting can also cause a race so we have to
1288 lwkt_gettoken(&q->p_token);
1289 p->p_flags |= P_CONTINUED;
1291 if (action == SIG_DFL)
1292 SIGDELSET_ATOMIC(p->p_siglist, sig);
1293 proc_unstop(p, SSTOP);
1294 lwkt_reltoken(&q->p_token);
1296 lwkt_reltoken(&p->p_token);
1297 if (action == SIG_CATCH)
1298 goto active_process;
1303 * If the process is stopped and receives another STOP
1304 * signal, we do not need to stop it again. If we did
1305 * the shell could get confused.
1307 * However, if the current/preempted lwp is part of the
1308 * process receiving the signal, we need to keep it,
1309 * so that this lwp can stop in issignal() later, as
1310 * we don't want to wait until it reaches userret!
1312 if (prop & SA_STOP) {
1313 if (lwkt_preempted_proc() == NULL ||
1314 lwkt_preempted_proc()->lwp_proc != p) {
1315 SIGDELSET_ATOMIC(p->p_siglist, sig);
1320 * Otherwise the process is stopped and it received some
1321 * signal, which does not change its stopped state. When
1322 * the process is continued a wakeup(p) will be issued which
1323 * will wakeup any threads sleeping in tstop().
1325 lwkt_reltoken(&p->p_token);
1331 /* else not stopped */
1335 * Never deliver a lwp-specific signal to a random lwp.
1338 /* NOTE: returns lp w/ token held */
1339 lp = find_lwp_for_signal(p, sig);
1341 if (SIGISMEMBER(lp->lwp_sigmask, sig)) {
1342 lwkt_reltoken(&lp->lwp_token);
1345 /* maintain proc token */
1348 lwkt_reltoken(&p->p_token);
1349 /* maintain lp token */
1355 * Deliver to the process generically if (1) the signal is being
1356 * sent to any thread or (2) we could not find a thread to deliver
1360 sigsetfrompid(curthread, p, sig);
1361 KNOTE(&p->p_klist, NOTE_SIGNAL | sig);
1362 SIGADDSET_ATOMIC(p->p_siglist, sig);
1367 * Deliver to a specific LWP whether it masks it or not. It will
1368 * not be dispatched if masked but we must still deliver it.
1370 if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) &&
1371 (p->p_flags & P_TRACED) == 0) {
1372 lwkt_gettoken(&p->p_token);
1374 lwkt_reltoken(&p->p_token);
1378 * If the process receives a STOP signal which indeed needs to
1379 * stop the process, do so. If the process chose to catch the
1380 * signal, it will be treated like any other signal.
1382 if ((prop & SA_STOP) && action == SIG_DFL) {
1384 * If a child holding parent blocked, stopping
1385 * could cause deadlock. Take no action at this
1388 lwkt_gettoken(&p->p_token);
1389 if (p->p_flags & P_PPWAIT) {
1390 sigsetfrompid(curthread, p, sig);
1391 SIGADDSET_ATOMIC(p->p_siglist, sig);
1392 lwkt_reltoken(&p->p_token);
1397 * Do not actually try to manipulate the process, but simply
1398 * stop it. Lwps will stop as soon as they safely can.
1400 * Ignore stop if the process is exiting.
1402 if ((p->p_flags & P_WEXIT) == 0) {
1404 proc_stop(p, SSTOP);
1406 lwkt_reltoken(&p->p_token);
1411 * If it is a CONT signal with default action, just ignore it.
1413 if ((prop & SA_CONT) && action == SIG_DFL)
1417 * Mark signal pending at this specific thread.
1419 sigsetfrompid(curthread, p, sig);
1420 spin_lock(&lp->lwp_spin);
1421 SIGADDSET(lp->lwp_siglist, sig);
1422 spin_unlock(&lp->lwp_spin);
1428 lwkt_reltoken(&lp->lwp_token);
1431 lwkt_reltoken(&p->p_token);
1437 * Notify the LWP that a signal has arrived. The LWP does not have to be
1438 * sleeping on the current cpu.
1440 * p->p_token and lp->lwp_token must be held on call.
1442 * We can only safely schedule the thread on its current cpu and only if
1443 * one of the SINTR flags is set. If an SINTR flag is set AND we are on
1444 * the correct cpu we are properly interlocked, otherwise we could be
1445 * racing other thread transition states (or the lwp is on the user scheduler
1446 * runq but not scheduled) and must not do anything.
1448 * Since we hold the lwp token we know the lwp cannot be ripped out from
1449 * under us so we can safely hold it to prevent it from being ripped out
1450 * from under us if we are forced to IPI another cpu to make the local
1453 * Adjustment of lp->lwp_stat can only occur when we hold the lwp_token,
1454 * which we won't in an IPI so any fixups have to be done here, effectively
1455 * replicating part of what setrunnable() does.
1458 lwp_signotify(struct lwp *lp)
1462 ASSERT_LWKT_TOKEN_HELD(&lp->lwp_token);
1463 dtd = lp->lwp_thread;
1466 if (lp == lwkt_preempted_proc()) {
1468 * lwp is on the current cpu AND it is currently running
1469 * (we preempted it).
1472 } else if (lp->lwp_flags & LWP_SINTR) {
1474 * lwp is sitting in tsleep() with PCATCH set
1476 if (dtd->td_gd == mycpu) {
1480 * We can only adjust lwp_stat while we hold the
1481 * lwp_token, and we won't in the IPI function.
1484 if (lp->lwp_stat == LSSTOP)
1485 lp->lwp_stat = LSSLEEP;
1486 lwkt_send_ipiq(dtd->td_gd, lwp_signotify_remote, lp);
1488 } else if (dtd->td_flags & TDF_SINTR) {
1490 * lwp is sitting in lwkt_sleep() with PCATCH set.
1492 if (dtd->td_gd == mycpu) {
1496 * We can only adjust lwp_stat while we hold the
1497 * lwp_token, and we won't in the IPI function.
1500 if (lp->lwp_stat == LSSTOP)
1501 lp->lwp_stat = LSSLEEP;
1502 lwkt_send_ipiq(dtd->td_gd, lwp_signotify_remote, lp);
1506 * Otherwise the lwp is either in some uninterruptible state
1507 * or it is on the userland scheduler's runqueue waiting to
1508 * be scheduled to a cpu, or it is running in userland. We
1509 * generally want to send an IPI so a running target gets the
1510 * signal ASAP, otherwise a scheduler-tick worth of latency
1513 * Issue an IPI to the remote cpu to knock it into the kernel,
1514 * remote cpu will issue the cpu-local signotify() if the IPI
1515 * preempts the desired thread.
1517 if (dtd->td_gd != mycpu) {
1519 lwkt_send_ipiq(dtd->td_gd, lwp_signotify_remote, lp);
1526 * This function is called via an IPI so we cannot call setrunnable() here
1527 * (because while we hold the lp we don't own its token, and can't get it
1530 * We are interlocked by virtue of being on the same cpu as the target. If
1531 * we still are and LWP_SINTR or TDF_SINTR is set we can safely schedule
1532 * the target thread.
1535 lwp_signotify_remote(void *arg)
1537 struct lwp *lp = arg;
1538 thread_t td = lp->lwp_thread;
1540 if (lp == lwkt_preempted_proc()) {
1543 } else if (td->td_gd == mycpu) {
1544 if ((lp->lwp_flags & LWP_SINTR) ||
1545 (td->td_flags & TDF_SINTR)) {
1550 lwkt_send_ipiq(td->td_gd, lwp_signotify_remote, lp);
1551 /* LWPHOLD() is forwarded to the target cpu */
1556 * Caller must hold p->p_token
1559 proc_stop(struct proc *p, int sig)
1564 ASSERT_LWKT_TOKEN_HELD(&p->p_token);
1567 * If somebody raced us, be happy with it. SCORE overrides SSTOP.
1570 if (p->p_stat == SCORE || p->p_stat == SZOMB)
1573 if (p->p_stat == SSTOP || p->p_stat == SCORE ||
1574 p->p_stat == SZOMB) {
1580 FOREACH_LWP_IN_PROC(lp, p) {
1582 lwkt_gettoken(&lp->lwp_token);
1584 switch (lp->lwp_stat) {
1587 * Do nothing, we are already counted in
1594 * We're sleeping, but we will stop before
1595 * returning to userspace, so count us
1596 * as stopped as well. We set LWP_MP_WSTOP
1597 * to signal the lwp that it should not
1598 * increase p_nstopped when reaching tstop().
1600 * LWP_MP_WSTOP is protected by lp->lwp_token.
1602 if ((lp->lwp_mpflags & LWP_MP_WSTOP) == 0) {
1603 atomic_set_int(&lp->lwp_mpflags, LWP_MP_WSTOP);
1610 * We might notify ourself, but that's not
1616 lwkt_reltoken(&lp->lwp_token);
1620 if (p->p_nstopped == p->p_nthreads) {
1622 * Token required to interlock kern_wait(). Reparenting can
1623 * also cause a race so we have to hold (q).
1627 lwkt_gettoken(&q->p_token);
1628 p->p_flags &= ~P_WAITED;
1630 if ((q->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0)
1631 ksignal(p->p_pptr, SIGCHLD);
1632 lwkt_reltoken(&q->p_token);
1638 * Caller must hold p_token
1641 proc_unstop(struct proc *p, int sig)
1645 ASSERT_LWKT_TOKEN_HELD(&p->p_token);
1647 if (p->p_stat != sig)
1650 p->p_stat = SACTIVE;
1652 FOREACH_LWP_IN_PROC(lp, p) {
1654 lwkt_gettoken(&lp->lwp_token);
1656 switch (lp->lwp_stat) {
1659 * Uh? Not stopped? Well, I guess that's okay.
1662 kprintf("proc_unstop: lwp %d/%d not sleeping\n",
1663 p->p_pid, lp->lwp_tid);
1668 * Still sleeping. Don't bother waking it up.
1669 * However, if this thread was counted as
1670 * stopped, undo this.
1672 * Nevertheless we call setrunnable() so that it
1673 * will wake up in case a signal or timeout arrived
1676 * LWP_MP_WSTOP is protected by lp->lwp_token.
1678 if (lp->lwp_mpflags & LWP_MP_WSTOP) {
1679 atomic_clear_int(&lp->lwp_mpflags,
1684 kprintf("proc_unstop: lwp %d/%d sleeping, not stopped\n",
1685 p->p_pid, lp->lwp_tid);
1691 * This handles any lwp's waiting in a tsleep with
1698 lwkt_reltoken(&lp->lwp_token);
1703 * This handles any lwp's waiting in tstop(). We have interlocked
1704 * the setting of p_stat by acquiring and releasing each lpw's
1711 * Wait for all threads except the current thread to stop.
1714 proc_stopwait(struct proc *p)
1716 while ((p->p_stat == SSTOP || p->p_stat == SCORE) &&
1717 p->p_nstopped < p->p_nthreads - 1) {
1718 tsleep_interlock(&p->p_nstopped, 0);
1719 if (p->p_nstopped < p->p_nthreads - 1) {
1720 tsleep(&p->p_nstopped, PINTERLOCKED, "stopwt", hz);
1729 kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout)
1731 sigset_t savedmask, set;
1732 struct proc *p = curproc;
1733 struct lwp *lp = curthread->td_lwp;
1734 int error, sig, hz, timevalid = 0;
1735 struct timespec rts, ets, ts;
1740 ets.tv_sec = 0; /* silence compiler warning */
1741 ets.tv_nsec = 0; /* silence compiler warning */
1742 SIG_CANTMASK(waitset);
1743 savedmask = lp->lwp_sigmask;
1746 if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 &&
1747 timeout->tv_nsec < 1000000000) {
1749 getnanouptime(&rts);
1751 timespecadd(&ets, timeout);
1756 set = lwp_sigpend(lp);
1757 SIGSETAND(set, waitset);
1758 if ((sig = sig_ffs(&set)) != 0) {
1759 SIGFILLSET(lp->lwp_sigmask);
1760 SIGDELSET(lp->lwp_sigmask, sig);
1761 SIG_CANTMASK(lp->lwp_sigmask);
1762 sig = issignal(lp, 1, 0);
1764 * It may be a STOP signal, in the case, issignal
1765 * returns 0, because we may stop there, and new
1766 * signal can come in, we should restart if we got
1776 * Previous checking got nothing, and we retried but still
1777 * got nothing, we should return the error status.
1783 * POSIX says this must be checked after looking for pending
1787 if (timevalid == 0) {
1791 getnanouptime(&rts);
1792 if (timespeccmp(&rts, &ets, >=)) {
1797 timespecsub(&ts, &rts);
1798 TIMESPEC_TO_TIMEVAL(&tv, &ts);
1799 hz = tvtohz_high(&tv);
1804 lp->lwp_sigmask = savedmask;
1805 SIGSETNAND(lp->lwp_sigmask, waitset);
1807 * We won't ever be woken up. Instead, our sleep will
1808 * be broken in lwpsignal().
1810 error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz);
1812 if (error == ERESTART) {
1813 /* can not restart a timeout wait. */
1815 } else if (error == EAGAIN) {
1816 /* will calculate timeout by ourself. */
1823 lp->lwp_sigmask = savedmask;
1826 bzero(info, sizeof(*info));
1827 info->si_signo = sig;
1828 spin_lock(&lp->lwp_spin);
1829 lwp_delsig(lp, sig, 1); /* take the signal! */
1830 spin_unlock(&lp->lwp_spin);
1832 if (sig == SIGKILL) {
1845 sys_sigtimedwait(struct sigtimedwait_args *uap)
1848 struct timespec *timeout;
1854 error = copyin(uap->timeout, &ts, sizeof(ts));
1861 error = copyin(uap->set, &set, sizeof(set));
1864 error = kern_sigtimedwait(set, &info, timeout);
1868 error = copyout(&info, uap->info, sizeof(info));
1869 /* Repost if we got an error. */
1873 * This could transform a thread-specific signal to another
1874 * thread / process pending signal.
1877 ksignal(curproc, info.si_signo);
1879 uap->sysmsg_result = info.si_signo;
1888 sys_sigwaitinfo(struct sigwaitinfo_args *uap)
1894 error = copyin(uap->set, &set, sizeof(set));
1897 error = kern_sigtimedwait(set, &info, NULL);
1901 error = copyout(&info, uap->info, sizeof(info));
1902 /* Repost if we got an error. */
1906 * This could transform a thread-specific signal to another
1907 * thread / process pending signal.
1910 ksignal(curproc, info.si_signo);
1912 uap->sysmsg_result = info.si_signo;
1918 * If the current process has received a signal that would interrupt a
1919 * system call, return EINTR or ERESTART as appropriate.
1922 iscaught(struct lwp *lp)
1924 struct proc *p = lp->lwp_proc;
1928 if ((sig = CURSIG(lp)) != 0) {
1929 if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig))
1934 return(EWOULDBLOCK);
1938 * If the current lwp/proc has received a signal (should be caught or cause
1939 * termination, should interrupt current syscall), return the signal number.
1940 * Stop signals with default action are processed immediately, then cleared;
1941 * they aren't returned. This is checked after each entry to the system for
1942 * a syscall or trap (though this can usually be done without calling issignal
1943 * by checking the pending signal masks in the CURSIG macro).
1945 * This routine is called via CURSIG/__cursig. We will acquire and release
1946 * p->p_token but if the caller needs to interlock the test the caller must
1947 * also hold p->p_token.
1949 * while (sig = CURSIG(curproc))
1953 issignal(struct lwp *lp, int maytrace, int *ptokp)
1955 struct proc *p = lp->lwp_proc;
1961 int traced = (p->p_flags & P_TRACED) || (p->p_stops & S_SIG);
1966 * If this process is supposed to stop, stop this thread.
1968 if (STOPLWP(p, lp)) {
1969 lwkt_gettoken(&p->p_token);
1971 lwkt_reltoken(&p->p_token);
1975 * Quick check without token
1977 mask = lwp_sigpend(lp);
1978 SIGSETNAND(mask, lp->lwp_sigmask);
1979 if (p->p_flags & P_PPWAIT)
1980 SIG_STOPSIGMASK(mask);
1981 if (SIGISEMPTY(mask)) /* no signal to send */
1985 * If the signal is a member of the process signal set
1986 * we need p_token (even if it is also a member of the
1989 sig = sig_ffs(&mask);
1990 if (SIGISMEMBER(p->p_siglist, sig)) {
1992 * Recheck with token
1995 lwkt_gettoken(&p->p_token);
1997 mask = lwp_sigpend(lp);
1998 SIGSETNAND(mask, lp->lwp_sigmask);
1999 if (p->p_flags & P_PPWAIT)
2000 SIG_STOPSIGMASK(mask);
2001 if (SIGISEMPTY(mask)) { /* no signal to send */
2002 /* haveptok is TRUE */
2003 lwkt_reltoken(&p->p_token);
2006 sig = sig_ffs(&mask);
2009 STOPEVENT(p, S_SIG, sig);
2012 * We should see pending but ignored signals
2013 * only if P_TRACED was on when they were posted.
2015 if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) {
2016 spin_lock(&lp->lwp_spin);
2017 lwp_delsig(lp, sig, haveptok);
2018 spin_unlock(&lp->lwp_spin);
2020 lwkt_reltoken(&p->p_token);
2024 (p->p_flags & P_TRACED) &&
2025 (p->p_flags & P_PPWAIT) == 0) {
2027 * If traced, always stop, and stay stopped until
2028 * released by the parent.
2030 * NOTE: SSTOP may get cleared during the loop,
2031 * but we do not re-notify the parent if we have
2032 * to loop several times waiting for the parent
2033 * to let us continue.
2035 * XXX not sure if this is still true
2037 if (haveptok == 0) {
2038 lwkt_gettoken(&p->p_token);
2042 proc_stop(p, SSTOP);
2045 } while (!trace_req(p) && (p->p_flags & P_TRACED));
2048 * If parent wants us to take the signal,
2049 * then it will leave it in p->p_xstat;
2050 * otherwise we just look for signals again.
2052 spin_lock(&lp->lwp_spin);
2053 lwp_delsig(lp, sig, 1); /* clear old signal */
2054 spin_unlock(&lp->lwp_spin);
2057 /* haveptok is TRUE */
2058 lwkt_reltoken(&p->p_token);
2063 * Put the new signal into p_siglist. If the
2064 * signal is being masked, look for other signals.
2066 * XXX lwp might need a call to ksignal()
2068 SIGADDSET_ATOMIC(p->p_siglist, sig);
2069 if (SIGISMEMBER(lp->lwp_sigmask, sig)) {
2070 /* haveptok is TRUE */
2071 lwkt_reltoken(&p->p_token);
2076 * If the traced bit got turned off, go back up
2077 * to the top to rescan signals. This ensures
2078 * that p_sig* and ps_sigact are consistent.
2080 if ((p->p_flags & P_TRACED) == 0) {
2081 /* haveptok is TRUE */
2082 lwkt_reltoken(&p->p_token);
2088 * p_token may be held here
2090 prop = sigprop(sig);
2093 * Decide whether the signal should be returned.
2094 * Return the signal's number, or fall through
2095 * to clear it from the pending mask.
2097 switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) {
2098 case (intptr_t)SIG_DFL:
2100 * Don't take default actions on system processes.
2102 if (p->p_pid <= 1) {
2105 * Are you sure you want to ignore SIGSEGV
2108 kprintf("Process (pid %lu) got signal %d\n",
2109 (u_long)p->p_pid, sig);
2111 break; /* == ignore */
2115 * Handle the in-kernel checkpoint action
2117 if (prop & SA_CKPT) {
2118 if (haveptok == 0) {
2119 lwkt_gettoken(&p->p_token);
2122 checkpoint_signal_handler(lp);
2127 * If there is a pending stop signal to process
2128 * with default action, stop here,
2129 * then clear the signal. However,
2130 * if process is member of an orphaned
2131 * process group, ignore tty stop signals.
2133 if (prop & SA_STOP) {
2134 if (haveptok == 0) {
2135 lwkt_gettoken(&p->p_token);
2138 if (p->p_flags & P_TRACED ||
2139 (p->p_pgrp->pg_jobc == 0 &&
2141 break; /* == ignore */
2142 if ((p->p_flags & P_WEXIT) == 0) {
2144 proc_stop(p, SSTOP);
2148 } else if (prop & SA_IGNORE) {
2150 * Except for SIGCONT, shouldn't get here.
2151 * Default action is to ignore; drop it.
2153 break; /* == ignore */
2158 lwkt_reltoken(&p->p_token);
2164 case (intptr_t)SIG_IGN:
2166 * Masking above should prevent us ever trying
2167 * to take action on an ignored signal other
2168 * than SIGCONT, unless process is traced.
2170 if ((prop & SA_CONT) == 0 &&
2171 (p->p_flags & P_TRACED) == 0)
2172 kprintf("issignal\n");
2173 break; /* == ignore */
2177 * This signal has an action, let
2178 * postsig() process it.
2183 lwkt_reltoken(&p->p_token);
2186 spin_lock(&lp->lwp_spin);
2187 lwp_delsig(lp, sig, haveptok); /* take the signal! */
2188 spin_unlock(&lp->lwp_spin);
2191 lwkt_reltoken(&p->p_token);
2197 * Take the action for the specified signal from the current set of
2200 * haveptok indicates whether the caller is holding p->p_token. If the
2201 * caller is, we are responsible for releasing it.
2203 * This routine can only be called from the top-level trap from usermode.
2204 * It is expecting to be able to modify the top-level stack frame.
2207 postsig(int sig, int haveptok)
2209 struct lwp *lp = curthread->td_lwp;
2210 struct proc *p = lp->lwp_proc;
2211 struct sigacts *ps = p->p_sigacts;
2213 sigset_t returnmask;
2216 KASSERT(sig != 0, ("postsig"));
2219 * If we are a virtual kernel running an emulated user process
2220 * context, switch back to the virtual kernel context before
2221 * trying to post the signal.
2223 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
2224 struct trapframe *tf = lp->lwp_md.md_regs;
2226 vkernel_trap(lp, tf);
2229 KNOTE(&p->p_klist, NOTE_SIGNAL | sig);
2231 spin_lock(&lp->lwp_spin);
2232 lwp_delsig(lp, sig, haveptok);
2233 spin_unlock(&lp->lwp_spin);
2234 action = ps->ps_sigact[_SIG_IDX(sig)];
2236 if (KTRPOINT(lp->lwp_thread, KTR_PSIG))
2237 ktrpsig(lp, sig, action, lp->lwp_flags & LWP_OLDMASK ?
2238 &lp->lwp_oldsigmask : &lp->lwp_sigmask, 0);
2241 * We don't need p_token after this point.
2244 lwkt_reltoken(&p->p_token);
2246 STOPEVENT(p, S_SIG, sig);
2248 if (action == SIG_DFL) {
2250 * Default action, where the default is to kill
2251 * the process. (Other cases were ignored above.)
2257 * If we get here, the signal must be caught.
2259 KASSERT(action != SIG_IGN && !SIGISMEMBER(lp->lwp_sigmask, sig),
2260 ("postsig action"));
2263 * Reset the signal handler if asked to
2265 if (SIGISMEMBER(ps->ps_sigreset, sig)) {
2267 * See kern_sigaction() for origin of this code.
2269 SIGDELSET(p->p_sigcatch, sig);
2270 if (sig != SIGCONT &&
2271 sigprop(sig) & SA_IGNORE)
2272 SIGADDSET(p->p_sigignore, sig);
2273 ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
2277 * Set the signal mask and calculate the mask to restore
2278 * when the signal function returns.
2280 * Special case: user has done a sigsuspend. Here the
2281 * current mask is not of interest, but rather the
2282 * mask from before the sigsuspend is what we want
2283 * restored after the signal processing is completed.
2285 if (lp->lwp_flags & LWP_OLDMASK) {
2286 returnmask = lp->lwp_oldsigmask;
2287 lp->lwp_flags &= ~LWP_OLDMASK;
2289 returnmask = lp->lwp_sigmask;
2292 SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]);
2293 if (!SIGISMEMBER(ps->ps_signodefer, sig))
2294 SIGADDSET(lp->lwp_sigmask, sig);
2296 lp->lwp_ru.ru_nsignals++;
2297 if (lp->lwp_sig != sig) {
2300 code = lp->lwp_code;
2304 (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code);
2309 * Kill the current process for stated reason.
2312 killproc(struct proc *p, char *why)
2314 log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n",
2315 p->p_pid, p->p_comm,
2316 p->p_ucred ? p->p_ucred->cr_uid : -1, why);
2317 ksignal(p, SIGKILL);
2321 * Force the current process to exit with the specified signal, dumping core
2322 * if appropriate. We bypass the normal tests for masked and caught signals,
2323 * allowing unrecoverable failures to terminate the process without changing
2324 * signal state. Mark the accounting record with the signal termination.
2325 * If dumping core, save the signal number for the debugger. Calls exit and
2328 * This routine does not return.
2331 sigexit(struct lwp *lp, int sig)
2333 struct proc *p = lp->lwp_proc;
2335 lwkt_gettoken(&p->p_token);
2336 p->p_acflag |= AXSIG;
2337 if (sigprop(sig) & SA_CORE) {
2341 * All threads must be stopped before we can safely coredump.
2342 * Stop threads using SCORE, which cannot be overridden.
2344 if (p->p_stat != SCORE) {
2345 proc_stop(p, SCORE);
2348 if (coredump(lp, sig) == 0)
2354 * Log signals which would cause core dumps
2355 * (Log as LOG_INFO to appease those who don't want
2357 * XXX : Todo, as well as euid, write out ruid too
2359 if (kern_logsigexit) {
2361 "pid %d (%s), uid %d: exited on signal %d%s\n",
2362 p->p_pid, p->p_comm,
2363 p->p_ucred ? p->p_ucred->cr_uid : -1,
2365 sig & WCOREFLAG ? " (core dumped)" : "");
2368 lwkt_reltoken(&p->p_token);
2369 exit1(W_EXITCODE(0, sig));
2373 static char corefilename[MAXPATHLEN+1] = {"%N.core"};
2374 SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename,
2375 sizeof(corefilename), "process corefile name format string");
2378 * expand_name(name, uid, pid)
2379 * Expand the name described in corefilename, using name, uid, and pid.
2380 * corefilename is a kprintf-like string, with three format specifiers:
2381 * %N name of process ("name")
2382 * %P process id (pid)
2384 * For example, "%N.core" is the default; they can be disabled completely
2385 * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P".
2386 * This is controlled by the sysctl variable kern.corefile (see above).
2390 expand_name(const char *name, uid_t uid, pid_t pid)
2393 char buf[11]; /* Buffer for pid/uid -- max 4B */
2395 char *format = corefilename;
2398 temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT);
2401 namelen = strlen(name);
2402 for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) {
2404 switch (format[i]) {
2405 case '%': /* Format character */
2407 switch (format[i]) {
2411 case 'N': /* process name */
2412 if ((n + namelen) > MAXPATHLEN) {
2413 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
2414 pid, name, uid, temp, name);
2415 kfree(temp, M_TEMP);
2418 memcpy(temp+n, name, namelen);
2421 case 'P': /* process id */
2422 l = ksprintf(buf, "%u", pid);
2423 if ((n + l) > MAXPATHLEN) {
2424 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
2425 pid, name, uid, temp, name);
2426 kfree(temp, M_TEMP);
2429 memcpy(temp+n, buf, l);
2432 case 'U': /* user id */
2433 l = ksprintf(buf, "%u", uid);
2434 if ((n + l) > MAXPATHLEN) {
2435 log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n",
2436 pid, name, uid, temp, name);
2437 kfree(temp, M_TEMP);
2440 memcpy(temp+n, buf, l);
2444 log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format);
2448 temp[n++] = format[i];
2456 * Dump a process' core. The main routine does some
2457 * policy checking, and creates the name of the coredump;
2458 * then it passes on a vnode and a size limit to the process-specific
2459 * coredump routine if there is one; if there _is not_ one, it returns
2460 * ENOSYS; otherwise it returns the error from the process-specific routine.
2462 * The parameter `lp' is the lwp which triggered the coredump.
2466 coredump(struct lwp *lp, int sig)
2468 struct proc *p = lp->lwp_proc;
2470 struct ucred *cred = p->p_ucred;
2472 struct nlookupdata nd;
2475 char *name; /* name of corefile */
2478 STOPEVENT(p, S_CORE, 0);
2480 if (((sugid_coredump == 0) && p->p_flags & P_SUGID) || do_coredump == 0)
2484 * Note that the bulk of limit checking is done after
2485 * the corefile is created. The exception is if the limit
2486 * for corefiles is 0, in which case we don't bother
2487 * creating the corefile at all. This layout means that
2488 * a corefile is truncated instead of not being created,
2489 * if it is larger than the limit.
2491 limit = p->p_rlimit[RLIMIT_CORE].rlim_cur;
2495 name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid);
2498 error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP);
2500 error = vn_open(&nd, NULL,
2501 O_CREAT | FWRITE | O_NOFOLLOW,
2503 kfree(name, M_TEMP);
2509 nd.nl_open_vp = NULL;
2513 lf.l_whence = SEEK_SET;
2516 lf.l_type = F_WRLCK;
2517 error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0);
2521 /* Don't dump to non-regular files or files with links. */
2522 if (vp->v_type != VREG ||
2523 VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) {
2528 /* Don't dump to files current user does not own */
2529 if (vattr.va_uid != p->p_ucred->cr_uid) {
2535 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2537 VOP_SETATTR(vp, &vattr, cred);
2538 p->p_acflag |= ACORE;
2541 error = p->p_sysent->sv_coredump ?
2542 p->p_sysent->sv_coredump(lp, sig, vp, limit) : ENOSYS;
2545 lf.l_type = F_UNLCK;
2546 VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0);
2548 error1 = vn_close(vp, FWRITE, NULL);
2555 * Nonexistent system call-- signal process (may want to handle it).
2556 * Flag error in case process won't see signal immediately (blocked or ignored).
2562 sys_nosys(struct nosys_args *args)
2564 lwpsignal(curproc, curthread->td_lwp, SIGSYS);
2569 * Send a SIGIO or SIGURG signal to a process or process group using
2570 * stored credentials rather than those of the current process.
2573 pgsigio(struct sigio *sigio, int sig, int checkctty)
2578 if (sigio->sio_pgid > 0) {
2579 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred,
2581 ksignal(sigio->sio_proc, sig);
2582 } else if (sigio->sio_pgid < 0) {
2584 struct pgrp *pg = sigio->sio_pgrp;
2587 * Must interlock all signals against fork
2590 lockmgr(&pg->pg_lock, LK_EXCLUSIVE);
2591 LIST_FOREACH(p, &pg->pg_members, p_pglist) {
2592 if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) &&
2593 (checkctty == 0 || (p->p_flags & P_CONTROLT)))
2596 lockmgr(&pg->pg_lock, LK_RELEASE);
2602 filt_sigattach(struct knote *kn)
2604 struct proc *p = curproc;
2606 kn->kn_ptr.p_proc = p;
2607 kn->kn_flags |= EV_CLEAR; /* automatically set */
2609 /* XXX lock the proc here while adding to the list? */
2610 knote_insert(&p->p_klist, kn);
2616 filt_sigdetach(struct knote *kn)
2618 struct proc *p = kn->kn_ptr.p_proc;
2620 knote_remove(&p->p_klist, kn);
2624 * signal knotes are shared with proc knotes, so we apply a mask to
2625 * the hint in order to differentiate them from process hints. This
2626 * could be avoided by using a signal-specific knote list, but probably
2627 * isn't worth the trouble.
2630 filt_signal(struct knote *kn, long hint)
2632 if (hint & NOTE_SIGNAL) {
2633 hint &= ~NOTE_SIGNAL;
2635 if (kn->kn_id == hint)
2638 return (kn->kn_data != 0);